I did not want to write about an experience that happened two years ago, but I keep wondering about it and thought if I wrote it down maybe the wondering would go away if someone else said "hey, that happened to me." I do not recall the exact date, but it was September near midnight and the hot summer weather was changing. It was a full moon and I stepped out on my cement patio to feel the cool air. My dogs were up along the fence making their usual last leg lift before coming inside to sleep. They sleep inside because there are coyotes in the neighborhood. I live 15 miles north and a little east of town.

It was bright out and while reaching for a chair I looked down on the white cement and noticed a shadow. It was round. I looked up and there was nothing up there to be its cause. I looked on the roof -- perhaps a round object was up there that I didn't know about and it was casting a shadow down on the cement. Nothing on the roof. I looked in the black Locust tree, maybe there was a round nest up there and it was casting a shadow. All I saw was the shape of the tree and a little light coming through branches. It was bright out and I looked up a little to the left of the only tree in my yard. The moon was there a minute ago and it wasn't. There was no moon -- In the strangeness of the moment, I didn't put that piece into the puzzle until it was all over.

I was not frightened. I looked back down at the round shadow on the patio. Still there and it was about ten feet in diameter. I know because after the event I ran into the house and got a tape measure. But I'm getting ahead of myself.

Again I tried to find an overhead cause for the shadow on the patio and I was looking up and around and I noticed one of my dogs was watching something up in the sky. Every so often he would jump into the air like he was trying to catch something. I walked around looking up and I walked into the shadow and watching my shadow emerge when I stepped back out.

I stood quietly for maybe 45 seconds and I kept my eyes on it. I watched the shadow as it started to move across the patio. The one older dog, laying near my feet, jumped up and ran into the house and the other dog "followed" the shadow across the yard -- jumping up and down barking. I remember looking all around when it starte to move and I remember seeing the moon, and the shadow slowly moved off the patio down to the ground and the black circle moved slowly across the light colored sand. I was walking behind it and I could see my shadow to my left - on the left side of the shadow. The silent invisible round what-ever picked up speed, a perfect circle was right there to see and follow and I would have, but I was stopped by my fence. I watched it grow larger as it slithered across the yard and into the street. It was heading west north west. And then my dog stopped barking and leaping into the air and the shadow that had been on my patio for no more than two or three minutes had moved up and away.

Obviously when I first looked up at the full moon it wasn't there because the invisible round craft was between eleven and twelve o'clock position in the night sky and it was blocking my direct line of sight. It blocked the shape of the moon but the object in front of the moon gave itself away by casting a shadow on my patio. And I think it was close, maybe 50- 80 feet over my head (?) and that is why my dog was leaping into the air trying to catch it --- it was close enough to his senses to "leap up and catch." I saw nothing but a round shadow on the ground and I saw nothing to be the cause. The sky looked bright and normal for a full moon out in the country. No light pollution. There was no sound except my dog barking and just one other thing. When I went inside to get the tape measure, I noticed my five Koi were racing around their pond. As usual their covered porch, shades drawn, was in the dark and they should have been sleeping. How did they know there was a noiseless invisible, shadow casting, intruder? And why were they, and one dog upset, and I wasn't?